Oven door



F. A. GERCICH ET AL OVEN DOOR Filed Nov. 20. 1924 INVENTORS.

ATTOR'NEXZL '15 features of advantage, some of the: specification.

I .ingmade by the lbeoome P be @1927:

.IIP-ATENT 'oF'FI'c ---rnnnnmox 1.; (micron in Jesus '3'.

SIGNOBS '1'0 HAMMER-BEAT Olj OAKLAND, GAIJIOBNIA, 5' GO 203A- ,mrozsr or CALIFORNIA.

OVEN DOOR.

Application llledlovember :0, a4. Serial Io. 751,011.

Our invention relates 'to oven doors-and particularly tocounter-balancin means for oven doors arranged to swing at out a horizontal axis at their. lower edge;

- 6 An object of the invention s provide "an oven door with counter-balancing means which utilizes'atorsion spring without ne'cessita'tin" the external indication of the-pres.

' enoe 0 .such spring. e a

the invention is. to mevidea' counter-balancing device of the class described which will'allow the independent removal of a door from its frame. lOur invention possesses other the foregoing, will be set forth in the follow ing description ofthepref'erred form of our "inventi'on which is illustrated in the drawings accompanying and forming It is to be an erstoodthat. we do not limitourselvesto the show said. drawings and description; as we may adopt variations of the pre-' ferred form within the scope of our invenei tion as set forth in the'claims;

. I Referring to said drawings: 1

Figure 1 is a fragmentary inside sect onal view of an-oven equippedwiththe preferred embodiment of the device of-our invention,

. so the; oven door' being-in closed position.

ure 2, showing "another. embodiment of our s invention.

the springs have en arranged-in coaxlal relation with the pivotal axis of the doors,

and the structure involved has therefore necessitated the protrusion of one-or more parts ofthe stove adjacent the spring. But

present praetice in stove design has decreed that; stove. fronts shall be smooth and unbroken, with the result that previously used the use of counterconstructions involvin e torsion type have to" balancin s irings of t V o soete, and other'more comphca eans' of v counterbalancin have been refactorily applie objects and front when the door is in 0 en which, wlth this manner, thecounterba ancin structure art of trunnions gure-2 is a view 'similar to that 1of-Fig-' I we 1, showing the oven door: in open pos1- e 3 is a sectional view taken on the tofore, in oven doorsequipped with '4o counterbalancing spzing's of the torsion type,

V cured to the-side ted a portion 21of theflatter -fit in'the bearmg,so. that to. In accordance with our invention however, a structure is provided by which a torsion sprin may and :satissimplly for counterba aneing oven doors of the. usual type without presenting any external evidence of the presence or use of aspring. Briefly. expressed, the means of ourinvention comprises a torsion' ring 4 mounted behind the door frame an arranged to be actuated byatrunnion extendmg rearwardly from the door, the trunnion also preferably servingto provide a pivotal bearing for the doorand a stop to hold the door in perpendicularrelation to the stove sition. "In

isentirely -situated behind" the p aneg'of the stovefrontand therefore does not afiectthe external design of. the stove. i As here shown, the device of our-invention is applied to the door 6 of an even having a sidewall 7 and-a door frame 8. The door frame ishere shown'provided with I rfora-' 7 tions 9 adjacent the bottom of t e door opening therein, and arranged to reeeive 12 extending rearwardly from the lower edge of the door. j The, portion of the door adjacent the'lower edge '13- of each perforation 9 is preferably formed with'inv 'wardlv extending lugs '15- which cooperate,

with the edge 13 to provide a bearing of cir'- eular section which seats in a cooperating semicylindrical bearing recess'14- provided in 155 the lowerf forwardportion of the trunnion}.

In this manner, the pivotal axis of-the doorv is defined as the axis of thebearing recess 14, 1 and the hearing "so provided preventsoutdownward displacement' of 9o Word as well as p the door during itspivotal movement.

Oounterbalancing of the weight of the door as it is'lowered to its open position is v here shown provided for by means ofa torsion spring 16 formed spirally and loosely '95 mounted" in part on a cam shaft'17. Ashere shown, the shaft 17-'extend from and f is pivotally mounted in a bearing 18'provi ed in a; plate 19' which "is-,preferabl sewall 7 by-means of its 20. To provide a shaft bearing of n 8 T hWbearin "18 preferably exten halfway of 1% about i elengrh saunas 17,:-

n e l the outer eurfaee106 he within theportion iversely fro1n the plate. The other end 24 of the springis bent radially inward and is arranged to be fixed to the shaft by insertion in a radially extending socket 25 provided therein.

As here shown, the shaft 17 is arranged to be held in the bearing 18 by means of a .studbolt 26 and washer 27, the bolt head and washer being disposed in a countersunk portion 28 of the bearing. In this manner, when the plate is secured to the wall. 7 the studbolt 26 is prevented from becoming entirely disengaged from the shaft even though it may become loosened.

Operative connection between the spring and door is here shown provided by means of a cam connection between them. Fixed tothe outer end of the shaft 17 is a cam 29 which is arranged to cooperate with the trun:

nion 12 in applying the torsional strength of the spring 16 as a means for counterbalancing the door during its movement and when it is in lowered position. As here shown, the trunnion 12 is provided with a transverse notch 30 mediately of its outer edge and in which the end 31 of the can] is arranged to seat when the door is in raised position. The portion 32 of the trunnion edge portion below the notch 30 is preferab y smoothly curved so that as the trunnion is pivotally moved upward upon downward movement of the door, the cam end 31 will be simultaneously rotated upwardly and slidably engage the surface of the trunnion portion 32, it being noted that when the door is in fully extended position, as shown in Figure 2, the end 31 of the cam engages the trunnion edge portion 32 adjacent its extremity 33. The notch 30, it will now'be noted, serves to positively rotate the cam about its axis until the common contact point of the cam end and trunnion edge is above the plane determined by the cam axis and door-bearing axis, after which thei 'point 31 of the cam moves out of the notch and along the trunnion edge 32 as described. To insure a resilient pressure tending to maintain the door closed at alltimes, the spring 16 is preferably so shaped that slight tor 'sional distortion thereof will exist when the tion at all times, it being obvious that the efiective moment of such force, when the door is fully extended, is preferably slightly less than the weight moment of the door.

Preferably formed on the plate 19 at its front edge is a transversel extending flange 36 which is arranged to seat against the rear of the door' frame -8 and extends outwardly from the plate at least as far as the outer cam face 37; 13y referring Fig 'ure 2.it will now be seen that when; the

extended, the side 38 of the door is full notch 30 wii 1 enga e the inner face of the flange 36 to there y revent the further downward movemento the door, thus pro-. "7

viding a stop which will notpause an undu strain on the door frame. a

In the embodiment shown in 4, the operative relation between the. spring 41 and trunnion 42 is provided by tangentially extending the outer end 43 ofthe spring.

to operate in a groove 44 provided in the this form of the invention, the spring coils tending from the structure results.

rearward edgeof the trunnion. Since in n will now'be articunnynead that .a

counterbalancing means has :been'shown which permits the ready insertion or 'removal of the door trunnions in their perforations without ne'cessitatin any part of the counter ala'ncln'g mechathe "removal of nism. It will be further notedthat either one or both supporting trunnions of adoor may be provided with the counterbalancing means of our invention, or that one or more trunnions independent of the door supporting and pivoting means may be provided to. have the counterbalancing' device associated therewith.

' lVe claim: a

1. In anoven, a frame including a door frame, a door pivotally mounted at the lower edge of the opening in said door frame,

a cam shaft mounted for rotation about an axis parallel to and rearwardly of the bearing axis of said door, a bracket fixed-to said frame and provided with a bearing forsaidshaft, a coil spring mounted on said shaft tial movement of the other end of said spring; a cam lever fixed to said shaft, 9.

opened position, and said trunnion havinga depressed portion in which said cam is arranged to seat whenthe door is' in closed positiom i 2. In an oven, a door'frame, a door pivotally mounted at the lower edge of the opening in said door frame, a cam lever mounted for rotation about an axis parallel to and rearwardly of the bearing. axis of said door, a trunnion extending rom'said and having an end fixed thereto, means on m said bracket for preventing a circumferendoor and having a portion thereof arranged which said cam'is arranged to seat when to engage against and actuate said cam lethe door is in closed position. r p ver upon an opening movement of said door, In testimony whereof, We have hereunto and means associated with said cam lever set our hands at Oakland, California, this 5 operative to resiliently maintain said cam 15th day of November, 1924.

lever and trunnion in engagedrelation, said FREDERICK A. GERCICH. trunnion I having a depressed portion in JOSEPH B. GARDNER. 

